Bacillus Dysenteriae 577 



It is not improbable that the bacillus of Shiga is identical 

 with Bacterium coli, variety dysenteries, of Celli, Fioca, and 

 Scala,* a view that has been further confirmed by Flexner.f 

 It may also be identical with an organism described in 1 888 

 by Chantemasse and Widal.J 



Morphology. The organism is a short rod, very similar 

 to the typhoid and colon bacilli. It is feebly motile. 



Staining. When stained with methylene-blue the ends 

 color more deeply than the middle; and organisms from 

 old cultures show numerous involution forms and irregu- 

 larities. It stains with ordinary solutions, but not by 

 Gram's method. It has no spores, but has flagella (peri- 

 tricha). 



Cultivation. Colonies. The colonies upon gelatin 

 plates are small and dewdrop-like in appearance. Upon 

 microscopic examination they are seen to be regular and 

 of spheric form. By transmitted light they appear granular 

 and of a yellowish color. They do not spread out in a thin 

 pellicle like those of the colon bacillus, and there are no essen- 

 tial differences between superficial and deep colonies. 



Gelatin Punctures. The growth in the puncture culture 

 consists of crowded, rounded colonies along the puncture. 

 A grayish-white growth forms upon the surface. There is 

 no liquefaction of the gelatin. 



Agar-agar. Upon the surface of agar-agar cultures 

 kept in the incubating oven, large, solitary colonies are evi- 

 dent at the end of twenty-four hours. They are bluish- 

 white in color and rounded in form. The surface appears 

 moist. In the course of forty-eight hours a transparent 

 border is observed about each colony, and the bacilli of 

 which it is composed cease to stain evenly, presenting in- 

 volution forms. 



Glycerin agar-agar seems less well adapted to their growth 

 than plain agar-agar. Blood-serum is not a suitable 

 medium. 



Potato. Upon boiled potato the young growth resembles 

 that of the typhoid bacillus, but after twenty-four hours it 

 becomes yellowish-brown, and at the end of a week forms 

 a thick, brownish-pink pellicle. 



* "Hygien. Institut. Rom. Univ.," 1895, and "Centralbl. f. Bakt. 

 u. Parasitenk.," 1899. 



f "Univ. of Penna. Med. Bulletin," Aug. 1901. 



J See "Deutsche med. Wochenschrift," 1903, No. 12. 



37 



